Inhibition of topoisomerase II activity in repair-proficient CHO K1 cells by 2-[(aminopropyl)amino]ethanethiol (WR-1065)

摘要: The aminothiol 2-[(aminopropyl)amino]ethanethiol (WR-1065) is the active thiol of clinically studied radioprotective agent S-2-(3-aminopropylamino) ethylphosphorothioic acid (WR-2721). WR-1065 an effective radiation protector under in vitro conditions when it administered 30 min prior to exposure at a concentration 4 mM repair-proficient Chinese hamster ovary Kl cells (i.e., dose modification factor 1.4). In contrast, DNA double-strand break, repair-deficient xrs-5 cell line not protected these 1.0). Topoisomerase (topo) I and II activities protein contents were measured both lines found be similar magnitude. Neither radiation, WR-1065, or affected variables cells. WR 1065 was effective, however, reducing topo 11 activity by 2 line. Topo content, conditions. One several mechanisms protection attributed compounds has been their ability affect enzymatic reactions involved synthesis, repair, cycle progression. These results demonstrate modifying effect on specific nuclear enzyme (i.e.,more » type H topoisomerase), which synthesis. also suggest that differences do exist between enzymes isolated from parent mutant lines.« less